Sheet feeding apparatus



July 28, 1959 H. BARRATT ET AL swam FEEDING APPARATUS 4 Sheets-Sheet 2Filgd Jan. 7. 1957 AVI/E/v 702s: Hflnaw BARR/477" 717 lVsu/mv 541125-72United States Patent SEEET FEEDXNG APPARATUS Harold Barrett, ThomasNewton Forrester, and George Herbert Wilson, Coventry, England, assgnors to Courtaulds Limited, London, England, a British com- P yApplication January '7, 1957, Serial No. 632,748

Claims priority, application Great Britain January 11, 1956 12 Claims.(Cl. 271-6) This invention relates to sheet feeding apparatus and inparticular to apparatus for providing a substantially continuous flow ofsheets from a series of discrete stacks.

In the viscose industry, cellulose pulp in sheet form is one of thebasic raw materials. The pulp is usually delivered by the pulpmanufacturers baled in stacks from which the sheets are takenindividually for processing into alkali cellulose.

In one continuous method of manufacturing alkali cellulose, sheets ofcellulose pulp are fed in a continuous manner to a slurry tank in whichthe sheetsare immersed in an aqueous caustic soda solution and are tornto shreds by a stirring device.

One sheet feeding apparatus is described in USA. Patent No. 2,253,140 inwhich a stack of sheets of cellulose pulp maintained in an upstandingposition on a conveyor belt are fed at a predetermined speed to a bladesheet-separating means which reciprocates beneath the sheets and forcesone or more sheets at a time from the forward face of the stack. Inorder to load the conveyor with fresh sheets, it is necessary to stopthe operation of the machine while the loading is carried out manually.Such stoppages disturb the desired continuity of feeding. The sheets areplaced adjacent to each other in an upstanding manner and are supportedby sheet supporting members which are removed before reaching the bladesheet-separating means.

The object of the present invention is to provide a sheet feedingapparatus capable of delivering a substantially continuous flow ofsheets from discrete stacks.

According to the invention, mechanism'for feeding stacks of rigid sheetsto a picker operating at a uniform .when the last sheet of a stack hasbeen picked, and a feeler adapted to disengage the high speed drive andengage the low speed drive upon a stack being presented to the picker.

Preferably the mechanism also has mechanism by which the stacks ofsheets are turned into upstanding position at the picker. cradle inwhich the stacks are held while they are turned. The stacks may bedelivered to the cradle by a conveyor which is controlled by a switchwhich is actuated by a cradle when it is in position to receive a stack.

The picker may either be a blade reciprocated in an upwards directionfrom beneath the stack so as to slice off one sheet or more at a time,or may comprise a rotatable disc having a cut-away portion forming ablade at its periphery.

Three specific examples of apparatus constructed in accordance with theinvention are illustrated in the accompanying drawings in which,

Figure 1 is a front elevation of one form,

Figure 2 is a plan view of part of Figure 1 with a working part in asecond position,

The stacks may be turned by a 2,896,946: Patented July 28, 1959 iceFigure 3 is an end elevation of part of Figure l with the working partin a third position,

Figure 4 is an enlarged view of a detail of Figure 1,

Figure 5 is a diagram of the control mechanism,

Figure 6 is a front elevation of a second form,

Figure 7 is a plan view of part of Figure 6,

Figure 8 is a plan view of a second part of Figure 6,

Figure 9 is a front elevation of Figure 8,

Figure 10 is a front elevation of a third form,

Figure 11 is a plan view of Figure 10 through XIXI,

Figure 12 is an enlarged detail of Figure 10,

Figure 13 is an enlarged detail of Figure 11,

Figure 14 is a plan view of a driving mechanism for the apparatus shownin Figure 10,

Figure 15 is a diagram of a controller for the driving mechanism, and

Figure 16 is a schematic view of an electrically actuated, fluidpressure supply means for actuating certain parts of the mechanism ofthe present invention.

In Figures 1, 2 and 3 stacks 1 of cellulose pulp sheets 2 are deliveredby a conveyor belt 3 to a pusher or cradle 4 which lifts the sheets 2over a curved track 5 and delivers them to a rotating picker 6. Thepicker 6 peels the sheets 2 from the stack 1 and delivers them one byone to a delivery conveyor belt 7 by which they are conveyed to a slurrytank (not shown) where alkali cellulose is formed in a continuousmanner.

The pusher 4 is connected by two pivoted levers or arms 8, 9 to a framemember 11 and is caused to ride over the track 5 by means of a hydraulicram 11 connected to the lever 9.

When the empty pusher 4 is in its lowest position as shown in Figure 2it lies upon a bed 12 above which are supported two sets of rollers 13placed between prongs 14 of the pusher 4. A spring loaded stop 15 isdepressed by the central prong 14 which operates a switch 16 causing theconveyor belt 3 to deliver a stack 1 on to the rollers 13 above thepusher 4.

When the stack 1 is in position, it strikes a switch 17 which stops thebelt 3, causes a feeler in the shape of a rectangular frame 18 to beraised by a double acting pneumatic cylinder 19 into the path to betaken by the stack 1 and operates the ram 11 causing the pusher 4 torise.

The stack 1 is pushed along the track 5 and in order to maintain thefront sheet 2 of the stack 1 in a substantially perpendicular positionwith respect to the track 5, the pusher 4 for some part of the distanceis tilted forward (as shown in dotted outline at 20 in Figure 1) byvirtue of the disposition of the pivot points of the lovers 8, 9.

The stack 1 is pushed up the track 5 rapidly until the leading sheet 2strikes the frame 18 when the frame 18 exerts pressure on the stack 1due to the pneumatic cylinder 19 holding it in a vertical position(Figure 3). This pressure tends to straighten the stack 1 and prepare itfor the picker 6. The frame 18 is gradually moved against the pressurein the pneumatic cylinder 19 until a cam 21 fixed to the frame 18,releases a switch 22 which actuates an electrical circuit to open asource of air pressure to the appropriate end of the cylinder 19 causingthe frame 18 to swing outwards to a position shown in full line inFigure 1.

The switch 22 also causes the rate of movement of the pusher 4 to bereduced to a predetennined metering speed at which one sheet 2 ispresented to the picker 6 for each rotation of the picker 6.

The picker '6 (Figure 4) consists of a disc 23, having a blade 24 formedby cutting away a portion of the disc, mounted on a shaft 25 rotated bya driven belt 26 on a pulley Wheel 27. On each rotation of the picker .3.6, the blade 24 peels .a sheet 2 away from the stack 1 and guided by aplate 28 deposits it upon the belt 7. After one sheet 2 is removed, thestack 1 is moved up a rdistance equal to about the thickness of a singlesheet 2 in readiness for the next rotation of the picker.

When the last sheet 2 of the stack 1 has been picked, the pusher 4.isnow ,in such a position that a protruding member 29 strikes a switch .36which causes the pusher 4 to be rapidly returned to the bed 12 forloading with .a new stack 1.

The mechanism for :controlling the movement of the pusher is shown inFigure in which fluid pumped by a .pump33 immersed in a tank 34 anddriven by a motor 35 is delivered at .high pressure to the ram 11 by oneof two pipes 36, 37 selected by a four Way valve 38. Fluid is :alsocontinuously delivered to the ram 11 by a metering pump 39 which isconnected between the ttank34and the pipe 37 by a pipe 46. The valve 38is operated by two solenoids 41, 42.

With the :pusher 4- in the loading position, the opera- .tion :of theswitch 17 energizes the solenoid 42 and fluid from the pump 33 isdirected through a balance valve 43 and pipe 37 to the right-hand sideof the ram 11. :Fluid trapped in the left-hand side of the ram 11 by apiston 44 escapes by the pipe 36 the valve 38 and a .returnpipe 45 tothe tank 34. The pusher 4 rises ripidly until the switch 22 is operatedwhen the solenoid 42 is -de-energized. The valve 38 now blocks thesupply of fluid from the pump 33 and the pipe 36 remains connected tothe return pipe 45. Fluid pumped by the metering pump 39 continues toenter the right-hand side :of'the ram 11 and inches the pusher 4 forwardat a predetermined speed correlated with the speed of the rotation ofthe picker 6, for the duration of the picking tperiod.

When'the last sheet 2 is removed by the picker 4, the switch 30 isoperated as described above and the sole- :noid 4-1 is energized. Fluidfrom the pump 33 is now directed by the valve 38 to the ram 11 by way ofthe .pipe 136 :and the pipe 37 is connected to the pipe 45 providing anescape for fluid trapped in the ram 11 to the right ofthe piston 41.

The balance valve 43 is set such that it will allow the how .of fluidfrom ram 11 to tank 34 via pipe 37, :valves 43, 38 and pipe 45, when thepressure caused by forcing the piston to the right exceeds thatdeveloped by the auxiliary pump 39, this balance valve 43 issubstantially closed to the fluid pumped through line 40 by theauxiliary pump 39 when this is used for moving the ram 11 to the leftand thus lifting the stack 1.

The pusher 4 eventually reaches the bed 12 where it is held by thepressure of the ram 11 until the switch 17 is operated by a new stack ofsheets 2 initiating another cycle.

The movement of the pusher 4 to and from the picking position is carriedout as speedily as practicable so :that there is substantially no delayin the continuous .delivery of sheets 2 along the conveyor belt 7 to theslurry tank.

In operation, a stack 1 comprising approximately five hundred sheets ispicked in about seven minutes and the time taken between picking thelast sheet 2 of one stack .1 and the first sheet 2 of the next stack 1is about seconds.

The apparatus shown in Figures 6, 7, 8 and 9 is similar to thatdescribed in respect of Figure 1 (like parts being given the samereference numerals) with the main exception that the reciprocatingpusher 4 is replaced by a number .of cradles 46 joined together bychains 47 to form a continuous belt, which is driven by either a:fastimotor .48, or a slow motor 49 through a gear box 550 a chain 51and a wheel 52.

The fast motor 48 is connected to the gear box 50 by atchain 53 whichdrives a sprocket 54- on .a shaft 55.

The slow motor 49 is connected to the gear box 50 by a chain 56 whichdrives a free-wheel 57 also mounted on the shaft 55.

The slow motor 49 normally drives the shaft 55 but is overridden by thefast motor 48, by virtue of the free wheel 57, when the fast motor 48 isbrought into operation.

Each cradle 46 has a base 58 with supporting prongs 5h and wheels 60 andis guided by rails 61 on the track 5. Additional rail guides 62 areprovided on the vertical portions of the rails 61. When the motor 48 isin operation, stacks 1 of sheets 2 are pushed up track 5 by the cradles46 and on arriving at the picking position make contact with the feelerframe 18 waiting in a standing position. The frame 18 eventually isthrown outwards when the switch 22 is released as previously described,and the motor 48 is switched ofi. The chains 47 are now driven by themotor 49 and the cradles 46 are advanced at a speed correlated with therate of rotation of the picker 6 to permit one sheet 2 at a time to beremoved by the picker 6. The sheets 2 fall on to the belt 7 by way ofthe plate 28 and a secondplate 63 slotted at the top to permit passageof the prongs 59 of'the cradles 46.

When the last sheet 2 of a stack 1 has been picked,

a projection 64 on the cradle 46 strikes a switch 120 which starts themotor 48 thuscausing the chains 4-7 to carry the cradles 46 at a fastspeed. At the same time,

the frame 18 is restored to its vertical position.

New stacks 1 are delivered to a slotted platform 121 having rollers (notshown) by a conveyor belt :122,-during the period when the cradlesdriven by motor 49 are advancing at a speed correlated with the rotationof picker 6. The new stack 1 when in position, strikes a switch 133 atthe rear of the platform 121 which stops the conveyor belt 122. The nextcradle 46, when driven by the fast motor 48, passes upwards through the.plat- .form 121, lifts the waiting stack 1 and carries it up track 5towards the picker 6. The switch 133 is released setting the belt 122 inmotion, and .a new stack 1 is delivered to the platform 121, the switch133 is again operated and the belt 122 is stopped. Meanwhile, anotherstack 1 is presented to the picker 6, the motor 48 is stopped and thechains 47 .are again driven at metering speed by the slow motor 49.

The picking period for a stack 1 of about five hundred sheets is aboutseven minutes and the time taken to bring a new stack 1 to the pickingposition on completion of the previous stack 1 is about ten seconds thusmaintaining a substantially continuous flow of sheets along the'belt 7.

In Figures 10 and 11, stacks -1 of sheets '-2 lying in a horizontalposition are brought by a conveyor 65 to a cradle formed by pairs ofrotatable arms at right angles in the form of a star .wheel 66 whichdeposits the stacks 1 in an upstanding position on an inclined conveyor67 upon which the stacks 1 are carried to a chisel-nosed reciprocatingpicker 68. The sheets are sliced from the stacks 1 by the picker .68 andare guided by a plate 69 on to a delivery conveyor 70.

The conveyor 65 comprises four spaced belts 71, driven by means notshown, between which pass the arms 72of the wheels 66. The inclinedconveyor 67 similarly comprises four spaced belts- 73 lying in line withthe belts 71. The belts 73 are driven by a series of rollers 74 which inturn .are driven from a driven shaft 75 through a spigot 76, a chain 77,spigot 78 and a shaft 79. The lower ends of the belts 73 pass round aseries of rollers 80 freely mounted on a shaft'81 to which are fixed thewheels: 66. The shaft 81 is driven by a chain 82 on a spigot 83 from adriving means not shown.

A stack I lifted from the conveyor 65 and deposited upon the conveyor 67by the wheel 66 is carried up'the conveyor 67 by projections 84 fixed atspaced intervals on the belts 73. Co-operating with the projections 84are arms 85 extending downwards from a belt 86 placed above the conveyor67. The belt 86 travels between two rollers 87, 88; the roller 87 beingconnected by a chain drive 89 to a spigot 90 on the shaft 79.

The stack 1 is carried up the conveyor 67 rapidly until the leadingsheet 2 strikes one or both of a pair of catch members 91 placed betweenand projecting above the belts 73 adjacent the picker 68. Each member 91(Figure 12) is L-shaped and is pivoted at one end to a switch 92 and iscapable of being lifted or lowered by a pneumatic cylinder 94, throughan arm 93.

When the projecting tip of the member 91 in the lifted position ispushed forward by the leading sheet 2, the switch 92 is operated and thespeed of the conveyor 67 is reduced to a metering speed so that sheets 2are sliced from the stack 1, one at a time for each reciprocation. Atthe same time, the member 91 is lowered away from the stack 1 by the arm93. The picker 68 is reciprocated by a crank 95. Placed in the spacebetween the belts 73 just in front of the path of reciprocation of thepicker 68 is a rocker 96 biased to one side as shown in full line inFigure 13. One arm of the rocker 96 is attached to a micro-switch 97.

The stack 1 holds the rocker 96 in a horizontal position during thepicking period, but when the last sheet 2 is removed it returns to itsnormal position, operating the switch 97 causing the conveyor 67 totravel at speed and deliver another stack 1 to the picker without delay.

The shaft 75 is driven rapidly during the delivery period and at apredetermined rate during the picking period through a clutch mechanismshown in Figure 14. A clutch plate 98 freely mounted on the shaft 75 isdriven by a chain 99 from a fast driving source (not shown) and a secondclutch plate 100 also freely mounted on the shaft 75 is driven by achain 101 from a slow driving source (not shown). Between the plates 98,100 slides a co-operating clutch plate 102 keyed to the shaft 75 andcapable of being pressed into contact with either the plate 98 or theplate 100 by an arm 103 operated by a pneumatic cylinder 104.

The speed of the conveyor 67 is controlled by an electro-pneumaticcontroller shown in Figure 15.

The pneumatic cylinders 94, 104 are both connected by two pipes 105, 106to a two-way valve 107 to which is connected a compressed air supplypipe 108 and two vent pipes 109. Pistons 110 of the valve 107 may beshifted to the left by a solenoid 111, when compressed air is directedfrom the pipe 108 to the pipe 105 and the pipe 106 is vented. Onde-energisation of the solenoid 111 a return spring 112 draws the piston110 to the right when the compressed air from the pipe 108 is directedto the pipe 106 and the pipe 105 is vented.

When compressed air is connected to the pipe 105, the arm 103 connectedto the cylinder 104 (Figure 14) slides the clutch plate 102 into contactwith the plate 98 and in consequence the conveyor 67 and the belt 86 aredriven at speed. Also, the members 91 are lifted so that their tipsstand proud of the conveyor 67.

When compressed air is connected to the pipe 106, cylinder 104 causesthe arm 103 to slide the clutch plate 102 into contact with the plate100 when the conveyor 67 is driven at the metered speed for picking.Also the members 91 are lowered into the spaces between the belts 73 ofthe conveyor 67 The solenoid 111 is energized by an electric currentfrom terminals 113 through a relay switch 114 closed by the energizingof a relay coil 115 in a secondary circuit supplied with electriccurrent through terminals 116.

The relay coil 1-15 is only energized when three switches in thesecondary circuit are closed, namely the microswitch 97 of the rocker 96and both switches 92 of the two members 91. A relay coil hold-on switch117 closed on energization of the relay coil 115 is connectedin-parallel with the micro-switch 97.

Figure 15 shows the position when a stack 1 has been picked and theconveyor 67 is being driven at speed to deliver a new stack 1 to thepicking position.

The rocker 96 is off-balance thus closing the switch 97, and the twoswitches 92 are closed while the tips of the members 91 are projectinginto the path of the advancing stack 1.

As the stack 1 approaches the picker 68 it strikes the rocker 96bringing it to a horizontal position thus opening the switch 97. This,however, does not atfect the relay coil 115 since an electric circuit isstill maintaine through the switch 117.

When the leading sheet 2 of the stack I eventually strikes any one ofthe members 91, the associated switch 92 is opened and the circuitthrough the relay coil 115 is broken. The switches 114 and 117 areopened, the solenoid 11-1 is de-energized, the pistons in the valve 107move to the right under the influence of the spring 112, and compressedair enters the pipe 106.

The conveyor 67 is now driven at a slow speed for picking and themembers 91 are withdrawn out of the path of the stack 1 when theswitches 92 again close. The rocker 96 is held in the horizontalposition by the weight of the sheets 2 in the stack 1 until, in duecourse, the last sheet 2 is picked. The rocker 96 then tips offbalanceso closing the switch 97. The circuit through the relay coil is againclosed and the coil 115 closes the switches 1 14, 117. The solenoid 111is energized, the pistons 110 of the valve 107 are moved to the left andcompressed air is connected to the pipe 105. Again, the conveyor 67 isdriven at speed and the members 91 are lifted so that their tips projectinto the path of the next advancing stack 1.

The stack 1 comprising approximately five hundred sheets is picked inabout seven minutes and the time taken between picking the last sheet 2of one stack 1 and the first sheet 2 of the next stack 1 is about fiveseconds.

Thus a substantially continuous flow of sheet 2 is maintained along theconveyor 70.

The means for actuating cylinder 19 under control of switch 22 may be ofany preferred or conventional construction, one form being illustratedschematically in Figure 16, wherein pneumatic cylinder 19 is connectedby two pipes .118 and 119 to a two-way, piston-type valve 123 and isprovided at its opposite ends with vent or discharge pipes 124 and 125.Valve 123 is connected by pipe 126 to a source of compressed air. Piston127 of valve 123 may be moved from its upper position where it closesthe adjacent end of pipe 118 as shown in Figure 16, to its lowermostposition by solenoid 128 when switch 22 is closed, whereon compressedair is passed from pipe 126, over the top of piston 127, through pipe118 and into the upper portion of cylinder 19 above the piston 129therein which forces said piston 129 and the parts connected therewithin a downward direction as viewed in Figure 16. During this operation,vent or discharge pipe 124 is closed and vent or discharge pipe is open.When switch 22 is opened, solenoid 128 is de-energized and a returnspring 130 moves the piston 127 of valve 123 upwardly to the positionshown in Figure 16, where it closes the adjacent end of pipe 118,whereupon compressed air is passed from pipe 126 through pipe .119 andinto the lower part of cylinder 19 below the piston 129 therein whichforces said piston 129 and the parts connected therewith in an upwarddirection as viewed in Figure 16. During this operation, vent ordischarge pipe 125 is closed and vent or discharge pipe 124 is open.

When it is desirable to feed a blend of varying types of pulp sheets toa slurry tank, this can readily be achieved by having two or more sheetfeeding machines, each Ti loaded with sheets of a particular'type ofpulp, ifeeding sheets at predetermined rates-toa common conveyor belt.

The 'speedat whichthe sheets are picked 'ineach of the machines maybecontrolled to suit operating conditions, for example, the speed'may becontrolled by the levelof liquid in the slurry tank or by a Weight belton which the sheets are fed to the slurry tank.

- What 'we claim is:

1. Apparatus for feeding stacks of rigid sheets of uniform thicknmsstack by stack to a picker operating at a uniform rate comprising atleast one carrier for carrying a stack to the picker, means to load astack onto the carrier, a high'speed driving mechanism to move'thecarrier to present the first sheet of the said stack to the picker, alow speed driving mechanism to move the car- 'rier to present subsequentsheets to the picker at a rate corresponding to the rate of operation ofthe "picker, a feeler operative upon a stack being presented to thepicker to disengage the high speed driving mechanism and engage the lowspeed driving mechanism, and a detector operative when the last sheet ofa stack has been picked to disengage the low speed driving mechanism andcause the high speed driving mechanism 'to present a loaded carrier tothe picker.

2. Mechanism according to claim '1, in which the feeler is adapted to beengaged by the leadingsheet of a stack upon arrival of the latter at'the picker, there being a switch adapted to be operated 'by the feelerwhen it is engaged by the leading sheet which switch disengages the highspeed drive and also causes the feeler ;to be moved clear of the sheets.

3. Mechanism according to claim lin which the detector is actuated bythe carrier.

4. Mechanism according to claim 1, comprising mechanism by which thestacks of sheets are turned into upstanding position for presentation tothe picker.

5. Mechanism according to claim 4, having a cradle for turning thestacks.

-6. Mechanism according to claim 5, in which there are swinging armscarrying the cradle at high speed from a charging position to thepicker, at slow speed while the sheets are being picked, and the cradleand arms are returned at 'high speed to the charging :position when thecradle is empty.

7. Mechanism according to claim 5 in which :there is a conveyor adaptedto deliver the stacks to the cradle, in combination with a switchcontrolling the conveyor and adapted to be actuated by a stack when itis-delivered 'to the cradle.

8. Mechanism according to claim 5 in which there is arr-endless conveyorcarrying the cradle, in combination with 'low speed and high speeddrives therefor.

9. Mechanism according to claim 8, having at least two cradles, one ofwhich is in position to be charged when another is feeding a stack tothe picker.

l0. Mechanism according to 'claim 9 in which-there is a platform toposition a stack for acceptance by :a cradle, in combination with a beltconveyor to deliver the stack to the platform and a stationary stopswitch positioned to be actuated by a-stack of sheets when the saidstack has been delivered by the conveyor to a position to be receivedby-the cradle, which switch acts *to stop the belt conveyor.

11. Mechanism according to claim 5, in which the cradle is formed byrotatable arms set at right ang'lesto each other, the means to load astack onto the carrier comprising a feed conveyor, and there being asloping belt conveyor for the carrier driven "by the "low speed and highspeed drives adapted to turn up the stacks of sheets on the sloping beltconveyor at 'a point some distance from the picker. I 12. Mechanismaccording to claim 1-1, in which 'a second sloping belt conveyor isarranged above the first belt conveyor andis driven by the sai'd lowspeed 'andh'ig'h speed drives, both conveyors having cooperating arms tocarry the stacks up the first sloping conveyor.

References Cited in the -file of this patent UNITED STATES PATENTS

